1. Assimp介绍，参考：opengl-Assimp，Assimp的作用已经说的非常清晰了
2. 编译参考：Assimp编译安装
图省事，mac上开发直接用brew install assimp，iOS/Android平台需要编译对应的库，需要自己编译
源码编译有两处坑：
2.1 Ver 3.3.1源码有笔误，编译报错，4.1+版本无此问题，亲测
code/D3MFImporter.cpp:230:29: error: invalid operands to binary expression ('float (*)(const char *, const char *)' and 'nullptr_t')
vertex.z = ai_strtof>(xmlReader->getAttributeValue(D3MF::XmlTag::z.c_str()), nullptr);
错误代码
去掉多余的 '>'即可
2.2 ld: library not found for -lminizip
github上也有人提问，参考：https://github.com/assimp/assimp/issues/2553
1）brew install minizip
3. 实现效果
3d模型效果
注意：模型比较大，相机z坐标调大到20
Camera camera(glm::vec3(0.0f, 0.0f, 20.0f));
4. 完整代码
4.1 工程目录
工程目录
4.2 主程序代码，model mess代码可以参考learnOpenGL教程
#include <glad/glad.h>
#include <GLFW/glfw3.h>
#define STB_IMAGE_IMPLEMENTATION
#include "stb_image.h"
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>
#include "Shader.h"
#include "camera.h"
#include "model.h"
#include <iostream>
void framebuffer_size_callback(GLFWwindow* window, int width, int height);
void processInput(GLFWwindow *window);
void mouse_callback(GLFWwindow* window, double xpos, double ypos);
void scroll_callback(GLFWwindow* window, double xoffset, double yoffset);
unsigned int loadTexture(char const * path);
// settings
const unsigned int SCR_WIDTH = 800;
const unsigned int SCR_HEIGHT = 600;
// camera
Camera camera(glm::vec3(0.0f, 0.0f, 20.0f));
float lastX = SCR_WIDTH / 2.0f;
float lastY = SCR_HEIGHT / 2.0f;
bool firstMouse = true;
// timeing
float deltaTime = 0.0f;
float lastFrame = 0.0f;
glm::vec3 lightPos(1.2f, 1.0f, 2.0f);
int main()
{
glfwInit();
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
#ifdef __APPLE__
glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
#endif
GLFWwindow* window = glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "LearnOpenGL", NULL, NULL);
if(window == NULL)
{
std::cout << "Failed to create GLFW window" << std::endl;
glfwTerminate();
return -1;
}
glfwMakeContextCurrent(window);
glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
glfwSetCursorPosCallback(window, mouse_callback);
glfwSetScrollCallback(window, scroll_callback);
// tell GLFW to capture our mouse
// 这一行，不注释也是ok的，隐藏鼠标
// glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);
if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
{
std::cout << "Failed to initialize GLAD" << std::endl;
return -1;
}
stbi_set_flip_vertically_on_load(true);
glEnable(GL_DEPTH_TEST);
Shader lightingShader("1.colors.vs", "1.colors.fs");
Shader lightCubeShader("1.light_cube.vs", "1.light_cube.fs");
Model ourModel("pack/backpack.obj");
while (!glfwWindowShouldClose(window)) {
float currentFrame = glfwGetTime();
deltaTime = currentFrame - lastFrame;
lastFrame = currentFrame;
//input
processInput(window);
//render
glClearColor(0.1f, 0.1f, 0.1f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
lightingShader.use();
//view/projection transformations
glm::mat4 projection = glm::perspective(glm::radians(camera.Zoom), (float)SCR_WIDTH/(float)SCR_HEIGHT, 0.1f, 100.0f);
glm::mat4 view = camera.GetViewMatrix();
lightingShader.setMat4("projection", projection);
lightingShader.setMat4("view", view);
// 世界地图转换
glm::mat4 model = glm::mat4(1.0f);
model = glm::translate(model, glm::vec3(0.0f, 0.0f, 0.0f));
model = glm::rotate(model, (float)glfwGetTime(), glm::vec3(0.0f, 1.0f, 0.0f));
// model = glm::rotate(model, glm::radians(55.0f), glm::vec3(1.0f, 0.0f, 0.0f));
// model = glm::rotate(model, glm::radians(55), glm::vec3(1.0f, 0.0f, 0.0f));
model = glm::scale(model, glm::vec3(1.0f, 1.0f, 1.0f));
lightingShader.setMat4("model", model);
ourModel.Draw(lightingShader);
glfwSwapBuffers(window);
glfwPollEvents();
}
glfwTerminate();
return 0;
}
bool startRecord = false;
void processInput(GLFWwindow *window)
{
if (glfwGetKey(window, GLFW_KEY_Y))
{
std::cout << "Y" << std::endl;
startRecord = true;
}
if (glfwGetKey(window, GLFW_KEY_N))
{
std::cout << "N" << std::endl;
startRecord = false;
}
if (startRecord) {
return;
}
if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
{
glfwSetWindowShouldClose(window, true);
}
if (glfwGetKey(window, GLFW_KEY_W) == GLFW_PRESS)
{
std::cout << "W" << std::endl;
camera.ProcessKeyboard(FORWARD, deltaTime);
}
if (glfwGetKey(window, GLFW_KEY_S) == GLFW_PRESS)
{
camera.ProcessKeyboard(BACKWARD, deltaTime);
}
if (glfwGetKey(window, GLFW_KEY_A) == GLFW_PRESS)
{
camera.ProcessKeyboard(LEFT, deltaTime);
}
if (glfwGetKey(window, GLFW_KEY_D) == GLFW_PRESS)
{
camera.ProcessKeyboard(RIGHT, deltaTime);
}
}
void framebuffer_size_callback(GLFWwindow* window, int width, int height)
{
glViewport(0, 0, width, height);
}
void mouse_callback(GLFWwindow* window, double xpos, double ypos)
{
if (startRecord) {
return;
}
if (firstMouse)
{
lastX = xpos;
lastY = ypos;
firstMouse = false;
}
float xoffset = xpos - lastX;
float yoffset = lastY - ypos;
lastX = xpos;
lastY = ypos;
camera.ProcessMouseMovement(xoffset, yoffset);
}
void scroll_callback(GLFWwindow* window, double xoffset, double yoffset)
{
camera.ProcessMouseScroll(yoffset);
}
// 通用纹理加载方法
unsigned int loadTexture(char const * path)
{
unsigned int textureID;
glGenTextures(1, &textureID);
int width, height, nrComponents;
unsigned char *data = stbi_load(path, &width, &height, &nrComponents, 0);
if(data)
{
GLenum format;
if (nrComponents == 1)
{
format = GL_RED;
}
else if (nrComponents == 3)
{
format = GL_RGB;
}
else if (nrComponents == 4)
{
format = GL_RGBA;
}
glBindTexture(GL_TEXTURE_2D, textureID);
glTexImage2D(GL_TEXTURE_2D, 0, format, width, height, 0, format, GL_UNSIGNED_BYTE, data);
glGenerateMipmap(GL_TEXTURE_2D);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
stbi_image_free(data);
}
else
{
std::cout << "Texture failed to laod at path: " << path << std::endl;
stbi_image_free(data);
}
return textureID;
}
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